Catheters are tube-like members inserted into the body for diagnostic or therapeutic reasons. One of the therapeutic procedures applicable to the present invention is known as percutaneous transluminal coronary angioplasty (PTCA). This procedure can be used, for example, to reduce arterial build-up of cholesterol fats or atherosclerotic plaque. Using a movable wire system, one could more readily select the desired coronary artery and reach smaller branches as movable guidewires are smaller and more flexible than the fixed wire systems. The catheter is subsequently tracked over the guidewire to the stenosis. The balloon at the distal end of the catheter is then inflated causing the site of the stenosis to widen. After the balloon is deflated, the catheter is withdrawn over the guidewire and another catheter can be slid into place over it if necessary.
Various versions of rapid exchange catheters, either coaxial or biaxial, are shown in the following patents: U.S. Pat. Nos. 4,762,129 and 5,232,445 issued to Bonzel, U.S. Pat. Nos. 5,040,548 and 5,061,273 issued to Yock, U.S. Pat. No. 4,748,982 issued to Horzewski, et at., U.S. Pat. No. 4,988,356 issued to Crittenden, U.S. Pat. No. 5,135,535 issued to Kramer and U.S. Pat. No. 5,180,367 to Kontos and assignee's WO 94/11053 issued to Ndondo-Lay et at.
The following are examples of spring coil catheters. Some catheters, such as the present assignee's 14K.TM. catheter and Thruflex.RTM. catheter to Solar and Roucher (shown in U.S. Pat. No. 4,917,666) are over-tile-wire catheters having spring coil lumens to improve the pushability of the catheter. At the same time, the spring coil is flexible laterally, with minimized kinking. In the present assignee's Gold X.TM. catheter, a coaxial rapid exchange catheter shown in U.S. Pat. No. 5,328,472 issued Jul. 12, 1994 to Steinke et at., the outer lumen is similarly made of a spring coil, with a core wire extending through a portion of the coil for added pushability. In the present assignee's Omniflex.TM. catheter to Buchbinder and Solar (shown generally in U.S. Pat. No. 4,723,936) as sold, a proximal hypotube about 3.81 cm (1.50 inches) long improves the handling of the catheter, which is otherwise formed of a spring coil.
The following illustrates proximal balloon bonds used in the prior art. Adhesives are used in U.S. Pat. No. 4,748,982 to Horzewski et at. (col. 3, lines 18-27); in U.S. Pat. No. 5,100,381 to Burns (bonding, col. 3, lines 16-17); in U.S. Pat. No. 5,154,725 to Leopold (Cyanoacrylate or Loctite.TM. 405, col. 5, lines 3-6); in U.S. Pat. No. 5,156,594 to Keith (Epoxy or Cyanoacrylate, col. 8 lines 18-21); in U.S. Pat. No. 5,156,595 to Adams (Epoxy, col. 3, lines 35-40); and in U.S. Pat. No. 5,290,230 to Ainsworth et al. (col. 6, lines 25-27).
Heat bonding is used in U.S. Pat. No. 4,782,834 to Maguire (col. 3, lines 48-50). Heat shrinking is used in U.S. Pat. No. 4,748,982 to Horzewski et at. (col. 3, lines 25-27.
What is needed is a method of bonding the proximal end of a balloon which is reliable, which results in a minimal proximal bond profile as well as minimizing manufacturing time. The bonding technique should apply when using dissimilar materials or when using spring coil technology. A flexible bond is desired to allow better tracking.